The present invention relates to the field of robotic insertion systems for the insertion of electrical components into circuit boards, and more particularly to an improved horizontal oscillatory feeder providing a high part mix.
Robotic systems are commonly used to insert electrical components into circuit boards. These systems automate the process of "stuffing" boards with electrical components. Typically a system will include robot which picks a component up at a pickup station and then inserts it at a predetermined location in a circuit board.
Many types of electrical components are delivered by the manufacturer to the board fabricator in tube magazines. For example, tube magazines are commonly used to store and ship dual in-line package (DIP) components. The components are removed from the tube magazines prior to pick up by the robot. There are available on the market today tube magazine feeder devices which hold a plurality of tube magazines in a stacked relationship, and unload the components in the lowermost tube onto a component track for delivery to the pickup station. After a tube is emptied, it is ejected from the feeder device and the next loaded magazine drops into the unloading position.
One tube magazine component feeder is described in U.S. Pat. No. 4,862,578, by Gregory W. Holcomb. The feeder described in this patent is adjustable to accommodate various tube magazine and component configurations, and is of a horizontal configuration, in that the components are fed along a horizontal track to a horizontally orientated pickup station. However, such a feeder is suitable for a high volume, single part feeding operation, since at any given time, the feeder will be configured for a particular component. A vibrating or "live" track section driven by vibratory unit delivers the components from the tube to a "dead" track section.
Conventional vibratory units which are used to move components along a track to a pickup station are in wide use. However, the operation of such vibratory units is very sensitive to the weight and length of the track and to the weight of the component. This is because the track is typically supported on spring elements, and a magnetic actuator used to impart energy to one of the spring elements. As a result, the force imparted to the components on the track has a substantial force component normal to the track, in addition to the desired force component in the direction of the track. As a result, if the vibrational force is too high, the components may actually be lifted off the track, and in extreme cases can be launched into the air from the track. Moreover, the longer the track, the more uneven the forces applied to components on the track. As a result, the conventional vibratory feeder is extremely sensitive to the weight of the component and requires fine tuning to obtain proper operation for a given type of component.
U.S. Pat. No. 4,910,859, by Gregory W. Holcomb, describes another type of tube magazine feeder configuration. At FIG. 22 the tube magazine feeders 907 are gravity fed, as opposed to the vibratory feed system used in the tube magazine feeder of U.S. Pat. No. 4,862,578. Moreover, the feeders 907 can be configured for a high part mix, since the various tube magazines can each hold a different type of part from the other magazines. However, a drawback to this type of feeder is that the robotic equipment which picks up parts from the feeder must be designed to operate at the angle at which the feeders are orientated, in this case 45 degrees from the horizontal, and then be rotated so that the gripped component is held at the horizontal. This increases the complexity of the robot end effector.
Another type of tube magazine feeder employs a tilting apparatus to tilt a plurality of tube magazines to gravity feed components to a pickup location, and then return the tube magazines to the horizontal. This approach requires the added complexity of the tilting apparatus, and can lead to component lead damage or bending if the component's feed travel is stopped by a lead stop element. If a body stop element is used, the body-to-lead variations from component to component can provide unreliable locating of the component leads in relation to pick-up robot.
It is therefore an object of this invention to provide an apparatus for reliably moving components along a track which is relatively insensitive to the mass of the component.
Another object of this invention to provide a horizontal oscillator feeder which provides a high part mix capability, which is relatively insensitive to the mass of the components, and which does not damage component leads.